With rapid development of electronic and information industries, computers and the peripheral device thereof become essential parts in our daily lives. In addition to the working purposes, computers can be employed as amusement tools. In the computer systems, input devices play important roles for communicating the computer and the user. The common input devices of the computer systems include for example mice, keyboards or a trackballs. Take a keyboard device having multiple keys for example. By depressing the keys of the keyboard device, corresponding instructions are inputted to the computer.
FIG. 1 is a schematic view illustrating the outward appearance of a conventional keyboard device. There are multiple keys mounted on the surface of the keyboard device 1. These keys include for example ordinary keys 10, numeric keys 11 and function keys 12. When one or more keys are depressed, the computer executes a corresponding function. For example, when the ordinary keys 10 are depressed, corresponding English letters or symbols are inputted into the computer system. The function keys 12 (F1˜F12) can be programmed to cause the application program to perform certain functions.
In the fabricating process of the keyboard device, a testing procedure is performed to assure normal functions of the keyboard device. The testing procedure includes testing the circuit board of the keyboard device and testing the overall functions of the assembled keyboard device. By testing the circuit board, the manufacturer could realize whether any defects are present in the circuit board. If the procedure of testing the circuit board is eliminated, the keyboard device needs to be dissembled to debug the circuit board after the keyboard device is assembled and some defects are found. It is troublesome and time-consuming to dissemble the keyboard device and debug the circuit board.
FIG. 2 is a schematic circuit diagram illustrating the internal circuitry of the conventional keyboard device. The keyboard device 1 includes a microprocessor 13 and a keyboard scanning matrix 14. The microprocessor 13 is connected with the keyboard scanning matrix 14 through multiple pins. The other parts of the microprocessor 13 are known in the art, and are not redundantly described herein. The keyboard scanning matrix 14 includes multiple scan input lines X0˜X7 and multiple scan output lines Y0˜Y17. The scan input lines X0˜X7 and the scan output lines Y0˜Y17 crisscross to define a plurality of keys on the surface of the keyboard device 1.
Since the keyboard scanning matrix 14 is an 8×18 matrix, there are a total of 144 intersection points correlating to 144 keys on the surface of the keyboard device 1. That is, if there are 144 keys on the surface of the keyboard device 1, the internal circuit of the keyboard device 1 should have at least 26 scan lines.
Hereinafter, a process of testing the keyboard circuit board according to the prior art will be illustrated with reference to FIG. 2. After the keyboard circuit board is produced, the keyboard circuit board is connected with a testing module. The testing module includes 26 switches and 26 light emitting diodes (LEDs). These 26 switches are respectively connected with the scan input lines X0˜X7 and the scan output lines Y0˜Y17. These 26 light emitting diodes are respectively connected with the 26 switches. Next, the 26 switches are manually depressed one by one. If the light emitting diode connected with the depressed switch illuminates, the scan input line or the scan output line that is connected with the depressed switch passes the test. On the other hand, if the light emitting diode connected with the depressed switch does not illuminate, the scan input line or the scan output line that is connected with the depressed switch fail to pass the test. In other words, the tester could discriminate whether the function of the keyboard circuit board is normal according to the illuminating statuses of the light emitting diodes.
Although the convention process for testing the circuit board is simple, there are still some drawbacks. For example, it is time-consuming and labor-intensive to successively test the switches. In addition, since too many keys need to be manually tested, the tester may repeatedly depress the same keys or miss depressing some keys. Under this circumstance, the testing procedure should be performed again. The manual testing process is ineffective and costly.